[A] Democratic Congress and a future Democratic president could still remove Kavanaugh from the Supreme Court if they wanted without needing to impeach him. There are two other ways to kick a sitting justice off the court — neither of which requires a supermajority.

In the first, a new president would nominate and the Senate would confirm by majority vote a justice — in this case Kavanaugh — to a different post on an intermediate court of appeals (say the D.C. Circuit, where Kavanaugh formerly served). The justice would, in effect, be demoted.

The move is admittedly unprecedented at the Supreme Court level. But it finds support in an 1803 Supreme Court case called Stuart v. Laird. The fading Federalist Party of John Adams had created 16 new federal judgeships in 1801 — in part to spare Supreme Court justices from having to “ride the circuit” and hear regional appellate cases. Thomas Jefferson’s Democratic-Republicans triumphed at the polls and abolished the new positions in 1802. A litigant who had a case before one of those defenestrated judges sued.

The Supreme Court unanimously rejected his challenge. Critically, the court also explicitly upheld part of the Democratic-Republicans' intervention that forced justices to sit as appellate judges against their will.

The Stuart decision reflects Congress’s broad power to structure“any Department,” including the federal courts. Stuart also suggests that individuals have no vested right to a particular set of judicial duties. That principle was applied in Stuart to Supreme Court justices. And it is hard to see why justices can be required by statute to sit on a circuit court some of the time but not all of the time (which would be the case if Kavanaugh were effectively demoted).

And the second way:

That brings us to the second alternative method of relieving a justice of his or her duties. In a 2006 article in the Yale Law Journal, two scholars (conservatives, as it happens), Saikrishna Prakash and Steven D. Smith, amassed historical evidence that the Framers understood the “good behavior” standard to be judicially, rather than just politically, enforceable.

...

As (roughly) proposed in the Yale article, Congress could pass a statute authorizing a specially constituted bench of federal judges — say, five randomly drawn judges — to determine whether a particular judge (here, Kavanaugh) had violated the “good behavior” standard. That special bench could hold a hearing and, if convinced by the evidence, make the requisite finding to trigger exit from the bench. This approach wouldn’t require a congressional supermajority. It would need a presidential signature.

Assuming this is a serious article, here are the obvious responses:

(1) Nothing in the Constitution suggests that a person nominated for a position must accept it. In the early post-ratification period, Presidents commonly ran into the problem that their proposed nominees declined the position; no one suggested the nominees had a constitutional duty to accept. Plus, even if Justice Kavanaugh accepted (re)appointment to the D.C. Circuit, that wouldn't remove him from the Supreme Court; it would give him two positions. Stuart v. Laird, cited by Professor Huq, does not even begin to suggest otherwise. The case, as he says, held that Congress could assign "circuit riding" duties to Supreme Court Justices. It did not say that by assigning circuit duties to Justices, it made them no longer Justices. It said that Congress could give them additional duties beyond sitting on the Supreme Court. (And in even engaging this argument, I'm making the very generous assumption that Congress could vary the duties of a single Justice by name, rather than varying the duties of the office of Supreme Court Justice, as in Stuart). In short, the idea that a Justice can be "removed" by appointing him to a different office against his will is just silly, on multiple dimensions.

(2) I like the impressively contrarian article by my colleague Steven Smith and my sometime co-author Saikrishna Prakash, cited by Professor Huq. But even if it's right, it doesn't show what Professor Huq thinks it shows, for a simple reason: under Article III, Section 1, Justices "shall hold their Offices during good Behavior." As the Prakash/Smith article makes clear, the idea (consistent with the plain text) is that a Justice may forfeit the office by bad behavior after appointment. As they say, "A forfeiture proceeding [such as they propose] determined whether someone had violated the conditions of his tenured grant." [p. 111, n. 157]. That is, the condition of tenure is good behavior while in office. So even if Justice Kavanaugh were shown to have engaged in bad behavior prior to appointment, that would not amount to violation of his duty to engage in good behavior in office. He is entitled to hold his office "during" good behavior; so as long as his behavior in office is good, he cannot be removed under this procedure, whatever he may have done previously. And you don't have to read the 60+ page Prakash/Smith article to see this -- all that's needed (as Justice Kavanaugh himself might say) is close attention to the constitutional text.